Centrifugal molding apparatus



DBC- 24, 1935- l-l. M. NAUGLE ET A1.

CENTRIFUGAL MOLDING APPARATUS giled April 6, 1933 5 Sheets-Sheet l Dec.24, 1935. H. M. NAUGLE ET AL 2,025,301

CENTRIFUGAL MOLDING APPARATUS Filed April 5, 1933 5 Sheets-Sheet 2 lINVENTORS if H M/Vauyle BY .J Townsend w ATTORNEYS CENTRIFUGAL MOLDINGAPPARATUS Filed April 6, 1933 5 Sheets-Sheet 5 INVENTORS HMA/mle BY A. JTownsend Patented Dec. `24, 1793.5

UNITED STATES PATENT OFFICE CENTRIFUGAL MOLDING APPARATUS ApplicationApril 6, 1933, Serial No. 664,727

12 Claims.

The invention relates to the casting of metal and more particularly toapparatusfor centrifugally molding or casting molten metal on acommercial scale to form preferably steel products`\` such as massivering blooms, slabs, billets and the like; and this application is acontinuation in part of the common subject matter relating toapparatusshown in our copending method and product applications filed,respectively, Septemn ber 18, 1931, Serial No. 563,583, matured inPatent No. 1,908,169, dated May 9, 1933, December 29,

1931, Serial No. 583,658, December 29, 1931, Serial No. 583,659, January26, 1932, Serial No. 588,945,

matured in Patent No. 1,908,170, dated May 9,

193,3, and May 6, 1933, Serial No. 669,711; and the apparatus shown,described and claimed herein constitutes improvements upon theVapparatus shown in our prior applications filed, respectively,

February 18, 1930, Serial No. 429,359, matured lil in Patent No.1,903,906, dated April 18, 1933, and

May 17, 1930,- Serial No. 453,311, matured in Patent No. 1,908,168,dated May 9, 1933, and in our prior Patent No- 1,882,516, dated. October11, 1932.

The centrifugal casting of massive blooms,

f' slabs, billets and the like preferably having cross sectional areasof sixteen square inches and upwards with minimum dimensions of threeinches and circumferential lengths of twenty-five feet and upwardsdirectly from molten metal, prefff" erably in accordance with themethods set forth in curcopending applications,` involves the use ofcentrifugal casting apparatus including an annular mold, a rotor for themold, a ladle for molten metal, a pouring lbox receiving molten 5 metalfrom the ladle for pouring into the mold, means for depositinginsulation .material upon the inner surface of molten metal poured'intothe mold, means for supporting said pouring box and insulatingdepositing means, and safety means if for the rotor and mold.

It is an object of the present invention to provide apparatus forcentrifugally casting massive ring blooms, slabs, billets'and the like,including an annular mold, having separable sections, preferably upperand lower substantially similar sections, and means for attaching andclamping the two separable mold sections together which will not loosenby the action of centrifugal force.

It is likewise an object of the present invention to provide centrifugalcasting apparatus with a table or rotor upon which an annular mold,preferably including separable sections, is removably mounted, as bybeing held in place by its own weight and preferably by engaginglcentering means carried by the rotor, to enable easy removal of the moldrfrom the rotor and replacement thereof by other molds; so as to providefor successively placing a series of molds upon the rotor for utilizingone rotor for casting successive quantities of molten metal from oneheat. y 5 It is also an object of the present invention to providecentrifugal casting apparatus with an annular mold made of metal inwhich a substantial mass of metal forms the mold walls and is so locatedor distributed, with respect to the l0 annular mold cavity formed `bythe mold walls, that the cooling of certain regions of' molten metalpoured into said mold cavity is accelerated or retarded, as the casemaybe, for controlling the rate and progress of cooling and solidicationof the molten metal in the mold cavity. Moreover, itiis an object of thepresent invention to provide centrifugal casting apparatus for carryingout certain of the methods, particularly set forth in our copendingapplication, Serial No. 20

563,583, matured in Patent No. 1,908,169; as by providing a mold havingWalls forming an annular mold cavity, and by providing certain portionsof said Walls with facings or insets of refractory or insulatingmaterial for retarding and 25 controlling the rate and progress ofcooling and solidication of molten Vmetal poured into and containedwithin the mold cavity, to bring the final place of solidication of themolten metal substantially at the inner surface of the ring formedthereby, substantially midway between the upper and lower faces thereofso as to pro'- duce a sound, homogeneous, centrifugally cast ring,bloom, slab, billet and the like free from blow holes, shrinkagecavities, and other similar imperfections. ,Y

Likewise, it is an object of the present invention to providecentrifugal casting apparatus for carrying out certain other methods,particularly set forth in our copending application, Serial No. 563,583,matured in Patent No. 1,908,169; as'byl providing a mold having wallsforming an annular mold cavity, and by providing at least that portionof the upper and lower mold walls which extend from the inner .edges ofsaid mold walls to approximatelythe inner surface of the centrifugally-molded ring to be formed in the mold cavity with facings or insets ofrefractory or insulating material for retarding or delaying the coolingand solidification of molten metal adjacent thereto, to eliminate theformation of objectionable ns and the like at and adjacent to the upperand lower inner annular corners of the cast ring, which ns if formed,would have to be removed prior to rolling, thus incurring extraoperations and decreasing yield.

Similarly, it is an object of the present invention to providecentrifugal casting apparatus for carrying out certain other methods,particularly set forth in our copending application, Serial No. 563,583,matured in Patent No. 1,908,169; as by providing a mold having upper,outer and lower walls forming an annular mold cavity, by extending saidlower mold wall inward from the mold cavity a substantial distance forreceiving molten metal poured thereon to be introduced into the moldcavity, and by providing said lower mold wall and its inwardly extendingportion with facings or insets of refractory or insulating material forpreventing the cooling and solidification of the molten metal as it isbeing poured upon the inwardly extending portion of the lower mold wall.

It is a further object of the present invention to provide the rotor ortable of centrifugal casting apparatus with a central vertical spindlewhich is journaled in anti-friction bearings for obtaining a smoothnessof operation of the rotor to prevent agitation of the molten metalwithin a mold .mounted on the rotor during solidif'lcation of the same;and to preferably provide a housing for the bearings in which thespindle is journaled, which also houses rotor driving connections.

Moreover, it is an object of the present invention to provide means forpreferably automati- ,cally regulating the retardation of rotation ofthe rotor of centrifugal casting apparatus after metal introduced into amold mounted on the rotor has `cooled to a self-sustaining plasticcondition, to prevent disintegration of the metal due to inertia. 1

It is a further object of the present invention to provide centrifugalcasting apparatus with a pouring ,box which receives molten metal from aladle and discharges the same to a rotating mold, with a spout ordischarge nozzle arranged or located to limit or prevent splashing anddripping.

It is also an object of the present invention-to provide means fordepositing or applying a blanket or coating of heat insulating orrefractory material, and/or pressure producing material to the innerface of molten metal within a rotating annular mold of centrifugalcasting apparatus,

immediately after the molten metal has been` poured therein,forrretarding the cooling and solidification ofthe molten metalthroughout theA entire area of the inner face portion ofthe ring untilthe cooling and solidication of the molten metal has progressed from theouter peripheral portion of the ring inward to the inner face thereof.i.

Similarly, it is a further object of the present invention to provideapparatus for depositing heat insulating or refractory, preferablylcomminuted, material upon the inner face of molten metal poured into arotating annular mold of centrifugal casting apparatus, immediatelyafter the pouring operation has been completed.

Furthermore, it is an object of the present invention to providecentrifugal castingapparatus with means for mounting the pouring box andi insulating material depositing means in proper and accurate positionwith respect to the rotating mold; said mounting means being arrangedfor quick removal of the pouring boxand insulating material depositingmeans immediately after the pouring operation has been completed,without the possibility of any of the parts striking rotating parts, soas to enable prompt remounted on the ,is journaled at vent coolingstrains. 5

Y Moreover, it is an object of the present invention to providecentrifugal casting apparatus with safety means and devices forprotecting the operators thereof from injury as by locating moying partsthereof within a compartment substan- 10 tially enclosed byv guards.

And finally, it is an object of the present invention to providecentrifugal casting apparatus in which all of the above desiderata areobtained in an expedient manner which enables the rapid 15 and economiccasting of massive ring blooms', slabs, billets and the like which arehomogeneous and free from defects throughout.

These and other objects may be obtained bythe apparatus, parts,combinations, devices, ele- 20 ments, arrangements, and meanshereinafter described in detail and claimed, preferred embodiments ofwhich are shown in the accompanying drawings, in which:-

Figure l is'an axial section of a preferred form 25 of the improvedcentrifugal casting apparatus taken as on the line 1-1, Fig. 2;

Fig. 2 is a plan view of the same; and

Fig. 3 is an enlargedv fragmentary section of a portion of the mold androtor. 30

Similar numerals refer to similar pa throughout the drawings.

The improved centrifugal casting apparatus is preferably mounted upon aprimary concrete foundation 4 in which a pit 5 is formed. A 35 flangedannular rotor supporting base 6 is foundation 4 and anchored theretopreferably by anchor means 1; and the base 6 preferably supports a driveand bearing housing generally indicated at 9, preferably com- 40 posedof an upper housing member 9 andv a lower housing member I0.

A combined thrust and radial anti-friction preferably tapered'rollerbearing II is preferably mounted at I2 in the upper housing member 45 9,and a combined thrust and radial anti-friction preferably tapered rollerbearing I3 is preferably mounted at I4 in the lower `housing member I0.

A vertical spindle I5, provided with ra flange I5,

I1 and I9, respectively, in the 50 bearings II and I3, and a bearingretaining disk I 9 is preferably mounted on the end of the spindle I5engaging the cone o f the bearing I3. A bearing lubricant retainingplate 2l is preferably bolted to the lower housing member III at '2| to55 enclose the bearing I3 and the lower end of the spindle I5; andlubricant seals 22 and 23 are preferably provided for the bearing Ilbetween the upper housingmember 9 and the spindlel l5.

A bevel gear 24 is mounted on the spindle I5 6o within the housing 9,and the gear 24 is driven by a bevel pinion 25, which is located withinthe housing 8 through an opening 23 provided in a wall of the lowerhousing member I0. The pinion 25 is mounted on one end of a shaft 21which 65 is journaled in bearings 29 and 29, and a gear 30 is mounted onthe other end of the shaft 21 within a gear housing 3l. A pinion 32,mounted on the motor shaft of the rotor drive motor 33, which issupported at 34 on the primary founda- 70 tion 4, drives the gear 33.

flanger I6. The table 35 is preferably provided with a fiat annularsurface 38, and a removable guard plate 39 preferably extends inwardfrom the fiat annular table top surface 38 to the hub portion 36 thereoffor enclosing the bolts 31. A cover plate 48 bolted to the spindle isalso preferably provided for the upper end of the spindle I5.

Centering means, which may either be blocks or an annular ring 4|, ispreferably provided by welding the s'ame at 42'to the rotorI or table 35for mounting and centering the annular mold, generally indicated at 43(Fig. 3) on' the rotor. The improved mold 43 preferably includes sepfarable halves or sections 44 and 45 having therebetween a substantiallyhorizontal joint 46 with an offset 41 therein, substantiallyin themedian plane of the mold; and abutting flanges 48 and 49 are provided onthe mold sections 44 and 45, which are detachably clamped, joined, orsecured together by means such as pins 58, which engage the lower moldsection 44 and pass through the abutting fianges 48 and 49. and by wedgepins which engage the pins 59 and the upper mold section 45. l

The mold sections 44 and 45 comprise the upper metal mold wall 52, theouter metal mold wall 53 and the lower metal mold wall 54, which form anannular inwardly opening trapezoidal mold cavity 55 suitably shaped togive the desired section to a massive ring, preferably with the upperand lower wall mold cavity surfaces slightlyl tapered outward towardeach other, and with rounded corners between the upper, lower and sidewall mold cavity surfaces, as shown.

Moreover, there is a substantial mass of metal in the outer `metal moldwall 53, the upper metal mold wall 52, and the lower metal mcldwall 54;and there is a substantially greater mass of metal in the outer metalmold. wall 53 than ineither the upper metal mold wall 52 or the lowermetal -mold wall 54; and the total mass of metal in the said mold walls52, 53 and 54 is preferably greater than the mass of metal in the ringto be formed in the mold cavity 55, for a purpose which will behereinafter described.

The lower mold wall 54 is preferably extended radially inward asubstantial distance by an annular plate section 56 rabbeted at thejoint 51 to and supported on the lower mold section 44, and the innerannular surface of the plate 56 may preferably be tapered as at 58 forwedge engagement with the centering ring 4|.

The mold 43 which is removably mounted on the rotor 35, may be quicklyraised, together With the annular plate 56 and removed from the rotortable 35 by any suitable crane tackle (not shown), which may engage theflange 59 so that successive molds may be successively placed on therotor; and upon release of the pins 58 and 5|, the upper mold section 45may be removed from the lower mold section 44 by suitable crane tackle(not shown), which may engage the flange 59.

The upper and lower mold walls 52 and 54 are preferably providedwithdovetailed annular channels or recesses 60, and annular insets or 52and 54; and the-plate 56 is also preferably provided with a dovetailedannular channel or recess 62 in which is dovetailed an annular inset,facing or ring of heat insulating refractory material 63. The refractorymaterial rings 6| and 63 may be made of a series of arcuate nre bricksdovetailed into the channels and secured therein by fire clay cement 64,and the upper surface of the ring 63 is preferably slightly tapered tobe substantially parallel with the mold cavity surface of the upper moldwall 52.

A secondary concrete foundation 65 preferably substantially encloses therotor and mounting therefor, together with the mold carried thereby, byforming a compartment 66 in which the rotor is located; and a pluralityof overhanging arcuate guard plate brackets 61 are preferably anchoredto the foundation 65, at 68, to form a circular working floor above therotor with a central opening 69 therethrough slightly larger than theoutside dimensionsV of the mold 43.

The motor 33 and gear housing 3| are preferably located in a compartment69 formed' by walls provided with a cover plate 1| and the compartment69 is preferably separated from the compartment 66 by a guard vplate 12extending between the walls 18. Likewise, the compartmentl 66 isseparated from the pit 5 by a guard plate 13, which protects the shat 21and bearings 28 and 29 therefor.

Saddle boxes 14 are preferably mounted at 15 on the overhanging brackets61'at fdiametrically spaced portions of the opening 69 formed thereby;and each saddle box 14 preferably includes an end wall 16 and side walls11.

I-beams 18, secured together in spaced relation by spacers 19, form abridge generally indicated at 80, which may be removably supported orsuspended at its end portions in the saddle boxes 14; and the bridge 88is provided with a suitable I- frame 8| with which suitable crane tacklemay be engaged for hoisting the bridge 80 to remove the same from itslocation above the rotor.

A refractory lined pouring box 82, provided with a flared mouth 83, awell 84 and a spout having an orifice 85 therein, is mounted on thebridge 80 above the mold 43 with the spout located adjacent to the mold43; and a cartridge chute 86, prodischarge end 88 cut away at 88aadjacent to the mold 43 is also suspended or mounted on the bridge 88above the mold 43 for holding a prefer'- ably cartridge charge 89 ofpreferably comminuted refractory material.. The refractory material'charge 89 is preferably confined in measured amounts within a paper orfabric container and held within the cartridge chute by a bell crankstop 98 pivoted at 9| to the chute 86, and maintained in position by atrigger 92 which may be operated to discharge the material by releasingthe cartridge 89 by a pull line 93 leading to the operators station.

In utilizing the improved centrifugal casting apparatus. forcentrifuga-Hy casting molten metal to form massive ring blooms, slabs,billets and the like, raw materials, consisting preferably of scrapmetal and other necessary or desired refining and/or alloying materialsare melted and refined preferably in an eectric furnace. When the moltenmetal has the desired chemical characteristics and has a temperaturematerially above 2600 F., the same is tapped intol the ladle 94 whereinit is carried to a position over the centrifugal casting appartus, asshown in Fig. 1, and is there tapped into the pouring box v82, whence itflows into the annular mold cavity 55 of the rotating mold 43 whereinupon solidication, a massive ring bloom A is formed as shownparticularly in Fig. 3.

Immediately after the molten metal has been vided with a ared receivingend 81 and an open v heat insulating refractory preferably comminutedmaterial is preferably deposited on the inner face of the molten metalcontained within the mold cavity 55 by releasing the cartridge charge ofthe Same indicated at 89 which is held in the cartridge chute 86, sothat the comminuted material will l spread to form a blanket or coatingindicated by dotted lines at B in Fig. 3, upon the inner face of themolten metal. As soon as the molten metal has cooled to a selfsustainingplastic condition to form a ring A,

the ring A may be removed from the mold. This may be accomplished bypromptly removing the ladle 94 with a crane, after the pouring operationhas been completed, and then picking up the bridge by engaging theI-frame 8l with a crane hook to remove the bridge, and the pouring box82 and depositing means 86 carried thereby, from above the rotatingmold.

Meanwhile, when the molten metal within the mold cavity 55 cools to aself-sustaining plastic condition, the speed of rotation of the rotor 35is preferably automatically retarded by suitable control means,indicated diagrammatically at 91, which may preferably includeaccelerating switches, dynamic braking contactors, and positively drivencontact making means for automatically regulating the sequence andperiods of the operation of the same; for retarding the speed of themotor 33 and the rotor 35, so as to permit the ring A to shrink withoutdisintegration or rupture due to inertia and for bringing the rotor 35to rest at the proper time. Thereafter, crane means are engaged underthe moldflange 59 to remove the mold 43 from the rotor 35, whereupon anempty mold may be placed upon the rotor and another casting operationmay be performed.

'I'he mold 43 is preferably removed to a stripping table where the pins50 and'5l are released followed by a removal of the upper mold section45. The massive ring bloom A may then be stripped from the lower moldsection 54 and transferred preferably to a circular roller table wherethe same may be severed by a hot saw or shear to form one or morearcuate blooms which may be subsequently straightened and rolled to formsemi-finished or finished rolled steel products in accordance with themethod set forth in our copending application, Serial No. 603,764,matured in Patent No. 1,908,171, dated May 9, 1933.

The use of the pins 50 and wedge pins 5| provide means for clamping themold sections 44 and 45 together, which clamping means cannot loosen bythe action of centrifugal force during rotation of the rotor to permitthe mold sections to spread during a pouring operation; and the'saidclamping means is readily releasable and removable for stripping amolded ring A from the mold 43.

The loose mounting of mold 43 on the rotor 35, by its being held inplace by its own Weight, by having its sections joined togetherindependently of the rotor, and by engaging the centering means 4|provided on the rotor 43, provides for ease of removal and replacementof molds 43, thus making possible the casting of succeeding parts of aheat on vthe same rotor equipment.

The location of a substantial mass of metal in the outer metal mold wall53, and the upper and lower metal mold walls 52 and 54, and the locationof a substantially greater mass of metal in the outer mold wall 53 thanin either the upper orA the lower mold walls 52 and 54 because of therecesses 60 in said walls 52 and 54 provides for great heatabsorptionand dissipation particwalls 52 and 54, to accelerate thecooling and solidiiication of molten metal from which the outerperipheral portions of the ring A is formed, so that the solidif'icationof the molten metal forming the ring A initiates at the outer portionsof the ring and progresses from the outer portions thereof to the innerportions thereof.

The use of the annular insets of refractory material 6l in the upper andlower metal mold walls 52 and 54 retards the rate and progress ofcooling and solidiiieation ofthe molten metal at and adjacent to theupper and lower inner annular corners of the ring A, which aids inbringing the final placev of solidication of the molten metalsubstantially at the inner surface of the ring A and substantiallymidway vbetween the upper and lower 'faces thereof.

Moreover, so long as the annular insets of refractory material 6I extendat least from the inner edges 95 of the upper and lower mold walls 52and 54 to approximately the inner surface 96 of the centrifugally moldedring to be formed in the mold cavity, objectionable fins do not form atand adjacent to the upper andy lower inner annular corners of the ringA, which fins -if formed, must be removed prior to rolling, thusincurring extra operations and decreasing yield.

terial 63 as a facing for the annular plate 56 prevents a. chilling,cooling or solidication of the molten metaly as it is being poured fromthe pouring box into the mold cavity 55, when the molten metal beingpoured is received upon the upper surface of the refractory ring 63; andthis control of the cooling of the molten metal prevents solidication ofmolten metal outside of the mold cavity before it is thrown by`centrifugal force into the mold cavity, which would be objectionable.

Likewise, the use of the cartridge chute 86 as a means for distributinga blanket or coating of heat insulating or refractory material B and/orpressure producing material, upon the inner face of molten metalcontained within the mold cavity 55 immediately after the molten metalhas been poured therein, enables the cooling and solidication of themolten metal throughout the entire area of the inner face portion of thering to be retarded until the cooling and solidification of the moltenmetal has progressed from the outer peripheral portion of the ring AIinward to the inner face 96 thereof.

These various means for controlling the cooling and solidification ofthe molten metal so as to bring the final point of solidiiicationsubstantially at the inner surface 96 of the ring A, substantiallymidway between the upper and lower vertical spindle journaled inanti-friction bearings prevents agitation of the molten metal within therotating mold as the same ls'being subjected to the action ofcentrifugal force, so that the beneficial effects of pressure actingupon the molten Ametal during rapid cooling and solidification producessound, homogeneous castings fren from blow holes, shrinkage cavities,dendritic segregation, and the like.

'I'he provision of means for regulating the retardation of rotation ofthe rotor after the ring A has cooled to a self-sustaining plasticcondiltion, enables the speed of the rotor to be controlled so as toprevent disintegration or rupture of the metal due to inertia and topermit certain methods set forth in our Patent No. 1,882,516 to becarried out.

Thel use of the pouring box 82, having a well 84, and an oriflce 85 inthe discharge nozzle thereof, together with the location of thedischarge nozzle substantially as shown in the drawings, enables apouring operation to be carried out without a dripping or splashing ofthe molten metal.

The use of the saddle boxes "M, and the bridge upon which the pouringbox 82 and cartridge chute 86 are mounted, enables the pouringbox spoutand the discharge mouth of the cartridge (.hute to be accurately locatedwith reference to the mold. Moreover, the end wall 16 and side walls 11of the saddle boxes engage the ends o-f the bridge 80 in such a way thatin placing the bridge over or withdrawing the bridgefrom the rotor, thepouring box spout and cartridge chute discharge end are guided clear ofthe mold, thus eliminating any possibility of the same striking themold. Such an arrangement makes it possible to remove the bridge 8f)from above the rotating mold before the mold has been brought to rest,which therefore facilitates the ultimate vstripping of the ring A fromthe mold 43.

The location of the rotating parts within the compartments 5, 66, and69, all of which are substantially enclosed by guards, protects theoperators of the centrifugal casting apparatus from injury.

Accordingly, the improved centrifugal casting apparatus may be used formaking the improved product set forth in our copending application,Serial No. 669,711, preferably in accordance with the method set forthin our copending application, Serial No. 453,311, matured in Patent No.1,908,168.

We claimz- 1., In centrifugal casting apparatus, an annular moldcomprising upper, outer and lower metal mold walls having mold cavitysurfaces forming an annular inwardly opening mold cavity, said upper andlower mold walls being provided with annular recesses, and there beingannular insets of refractory material in said annular recesses havingsurfaces coextensive with the mold cavity surfaces of said upper andlower metal moldwalls.

2. In centrifugal casting apparatus, an annular mold comprising upper,outer and lower metal mold walls having mold cavity surfaces forming anannular inwardly opening mold cavity, rsaid upper and lower mold wallsbeing provided with dovetailed annular recesses, and there being annularinsets of refractory material in said dovetailed recesses havingsurfaces lcoextensive with the mold cavity surfaces of said upper andlower metal mold walls.

3. In centrifugal casting apparatus, an annular mold comprising upper,outer and lower metal mold walls having mold cavity surfaces forming anannular inwardly opening mold cavity, there being annular recessesprovided in said upper and lower metal mold walls extending from theinner edges of said mold walls to approximately the inner surface of thecentrifugally molded ring to be formed in the mold cavity, and therebeing annular insets of refractory material in said anvrotating therotor,and a cartridge chute adjametal mold walls.

4. In centrifugal casting apparatus, an annular mold comprising upper,outer'and lower metal 5 mold walls forming an annular inwardly openingmold cavity, said lower mold wall being extended inward a substantialdistance from said mold cavity for receiving molten metal to beintroduced into the mold cavity, and said inwardly extending 10 portionof said lower mold wall being provided with a facing of refractorymaterial.

5. In centrifugal casting apparatus, an annular mold comprising upper,outer and lower annular metal mold walls having mold cavity surfaces 15forming an annular inwardly opening mold cavity, an annular plateextending inward a substantial distance from said mold cavity forreceiving molten metal to be introduced into the mold cavity, said upperand lower mold walls 20 and said annular plate each being provided withvided with annular recesses, there being annular insets of refractorymaterial in said annular re- 30 cesses having surfaces coextensive withthe mold cavity surfaces of said upper and'lower metal mold walls, saidupper and lower mold cavity surfaces and the refractory materialsurfaces c0- extensive therewith being tapered outward to'- 35 ward eachother, an annular plate extending inward from said lower mold wallasubstan'tial distance from said mold cavity for receiving molten metalto be introduced into the mold cavity, said annular plate being providedwith an annular 40 recess, and an annular inset of refractorymaterial insaid annular recess having a surface substantially parallel with theupper mold cavity surface.

7. In centrifugal casting apparatus, a rotor 45 minuted refractorymaterial adjacent to the mold,

and means for discharging said comminuted material into the mold cavity.60 9. In centrifugal casting apparatus, a rotor, an annular moldcomprising walls formingan annular inwardly opening mold cavity, meansfor cent to the mold provided wana receiving end, 65 an open dischargeend and means for holding a cartridge charge of comminuted material insaid chute and for discharging the same into the mold cavity. v 70 10.In centrifugal casting apparatus, a rotor mounted for rotation on avertical axis, an annular mold mountedon the rotor, means for rotatingthe rotor, a pouring box located above the mold for discharging moltenmetal into the mold, r insulation material depositing means located oabove the mold, for discharging refractory material into the mold, andmounting means for said pouring .box and insulating material depositingmeans removably suspended above the mold.

11. In centrifugal casting apparatus, a rotor, an annular mold mountedon the rotor, means for rotating the rotor, a bridge, means forremovably supporting the bridge above the mold, a pouring box mounted onthe bridge having a discharge nozzle normally located adjacent to saidmold for discharging molten metal into the mold, and means mounted onsaid bridge having a discharge end normally located adjacent to saidmold for supporting andA discharging refractory material into the mold.

12. Centrifugal casting apparatus, including a rotor, a central verticalspindle for said rotor, a rotor supporting base, anti-friction bearingsmounted on said base, said spindle being journaled in said bearings,means for rotating said spindle, means for regulating retardation ofrotation of the rotor, centering means on the rotor, an annular moldcomprising separable sections forming an annular inwardly opening moldcavity, means for clamping themold sections together including pinsengaging one of the mold sections and wedge pins engaging said othermold section and said pins, a third section inwardly extending from andrabbeted to one of said sections, a surface of said third sectionengaging said centering means, said st two mentioned sections formingupper, outer and lower metal mold walls, said outer, upper and lowermold walls comprising a substantial mass of metal, said mold sectionsand said third section each being provided l with annular recesses,there being annular insets of refractory material in said annularrecesses, a

bridge, means for removably supporting the bridge above the mold, apouring vbox mounted on the bridge above the mold, means mounted on thebridge above the mold for discharging heat insulating material into themold cavity, and guard means forming a compartment substantially enzoclosing said rotor and mold.

HARRY M. NAUGLE. ARTHUR J. TOWNSEND.

